Speed Sensorless Control of Permanent Magnet Synchronous Motor

Abstract

Permanent Magnet Synchronous Motors (PMSMs) are used in places that require fast response and high performance. Because of the bad environment, sensorless control of PMSM became the most used technique to avoid using the encoders. Speed estimators are still suffering from ripples in both toque and speed which have a negative effect on the control performance. In this thesis, cascaded multilevel inverter feeds PMSM. The topology of the inverter design and switching process are based on achieving high voltage levels with less number of components than usually used to obtain the same voltage levels by the conventional design. The sensorless speed control of PMSM is carried out using the field oriented control system model. The control system is improved by using PMSM dynamic equation block to enhance reference voltage calculation accuracy. Model Reference Adaptive System (MRAS) is used for motor speed estimation. MRAS speed estimator is improved by adding a regulator to protect the system from small disturbances and to reduce speed and torque ripples. Ant Colony Optimization (ACO) algorithm is used to tune MRAS speed estimator to enhance system performance, and also to reduce the speed and torque ripple. The system modeling and simulation results were done by using MATLAB/Simulink. Simulation results proves the modification effect on enhancing the system response in dynamic and steady states.